Select a NTP server, using net time /setsntp:ntp-server. However "Only the domain controller that holds the PDC FSMO (Primary Domain Controller Flexible Single Master Operation) role can query an external time source to set the time."[1]

Start the W32time service with net start W32Time. You can also set the start option of the Windows Time Synchronization Service (W32Time) to Automatic, so the service will start when Windows/2000 starts.